Recently two discs were released which are entirely devoted to Heinrich Isaac. That doesn't happen very often: he was one of the most celebrated composers of his time, but in our time he is largely overshadowed by his contemporary Josquin Desprez. It seems that the remark of a contemporary that Josquin was the better composer has contributed to the relative neglect of Isaac's oeuvre. Isaac was a versatile composer and his output is very large; his main contribution to the sacred repertoire of his time are his mass compositions. Apart from 36 settings of the Ordinary he wrote a number of separate mass movements and a large number of Propers. The latter are included in the largest collection of sacred music by a single composer of the renaissance, the Choralis Constantinus, which was published in three volumes in 1550 and 1555 respectively.

If one looks at the list of pieces available on disc (Arkiv) it is evident that his secular songs and textless pieces have received most attention. In comparison his masses and motets are poorly represented. It is telling that no fewer than five of the eight pieces on the programme recorded by Cantica Symphonia are recorded for the first time. The disc of the Ensemble Gilles Binchois doesn't make mention of any first recordings, but it seems likely that the two pieces from the Choralis Constantinus are first recordings; the Missa Virgo prudentissima has been recorded by the Capella Cathedralis München, directed by Karl-Ludwig Nies (Christophorus, 1999). These two discs both focus on music which Isaac must have written in Italy, but otherwise they are quite different in repertoire and performance.

First some biographical data. Isaac was from Flanders or Brabant and was born somewhere between 1450 and 1455. In 1484 he is first mentioned, in the capacity as court composer in Innsbruck. By 1484 he was in Florence where he was in the service of the Medicis. He apparently always remained in contact with this powerful family, even though the latter were banished from Florence in 1494. Two years later Isaac entered the service of Emperor Maximilian I. When the Medicis returned to Florence and a member of the family was elected Pope as Leo X they granted Isaac a pension.

Guido Magnano, in his liner-notes to the Glossa disc, tells a story which bears witness to Isaac's versatility as a composer. "In a letter addressed to the Florentine ambassador to Rome, Lorenzo [de' Medici] indicated his intention of offering a collection of chansons to the Venetian ambassador with these words: 'If I knew what kinds he likes best, I could have served him better since Arrigo Isaac has composed these songs in different ways, both grave and sweet, and also capricious and ingenious. I shall send a selection from each style, and following the first 'tasting' I shall know which wine I shall need to serve.' In short, such was the variety and wealth of Isaac's compositions that Lorenzo was in a position to send an anthology as if it were a range of samples!"

The main work on Cantica Symphonia's programme is the Missa Misericordias Domini. The title has puzzled scholars: the text is from Psalm 42 but no liturgical melody with this incipit is known. However, the material which Isaac uses here has been identified as In focho in focho la mia vita passa, an Italian frottola. Giovanni Zanovello - also the author of the liner-notes to the Evidence disc - has come up with a solution. In Florentine confraternities it was common practice to sing frottolas on new sacred texts (contrafacta); in this case the text of Psalm 42 could have been used for the above-mentioned frottola.

The programme also includes a contrafactum of a piece from Isaac's pen: the motet La mi la sol, la sol la mi - originally written on a fantasia with that title - was published in 1504 by Petrucci in Venice with the text Rogamus te piissima Virgo Maria. The motet Inviolata, integra et casta es, Maria was also published by Petrucci, but without the name of the composer. On stylistic grounds it is attributed to Isaac. Two pieces in the programme have been preserved in instrumental versions and have been reconstructed with their original texts by Giuseppe Maletto: Ave regina coelorum and Sub tuum praesidium. The disc ends with a quite spectacular piece, the five-part O decus Ecclesiae: "O, honour of the Church, O Virgin, the most glorious of the world, welcome". It is based on the succession of the notes of the hexachord which are played here by the wind instruments.

The programme which has been recorded by the Ensemble Gilles Binchois is a kind of liturgical reconstruction of "a Florentine celebration, possibly during a visit of Pope Leo X, to whose influence Isaac owed the financial security of his last years", according to Giovanni Zanovello in the booklet. The Missa Virgo prudentissima is one of the relatively few in Isaac's oeuvre which is scored for six voices. Also notable is that it belongs to a group of pieces based on this Magnificat antiphon at First Vespers of the Feast of the Assumption (15 August). "The particular chant used by Isaac bears special melodic variants found in southern Germany, suggesting an association of the six-voice Mass with the Hapsburg court confirmed by its important parallels with the motet of the same name (...). Both the Mass and the motet were very likely conceived for Maximilian’s failed coronation in Rome." From this we may conclude that there is no real connection between this mass and Florence. Then why was it chosen as part of a "Florentine celebration"? Moreover, "the plainchant used in the six-voice Ordinary differs from the intonation used in Florence" and the Propers from the Choralis Constantinus - which open and close the programme - "never circulated in Italy, as far as we know". Zanovello therefore is right in calling this an "imaginary liturgy". I wonder whether there would have been a way to embed this mass into a more appropriate liturgical context.

One of the notable aspects of this mass is that the antiphon Virgo prudentissima is sung either at full length or in fragmentary form in one and/or two voices (superius and tenor respectively) in all sections, except the Agnus Dei. There are two Christe eleison settings which allow nine statements of the invocation Kyrie - Christe - Kyrie, alternating between polyphony and plainsong. The Agnus Dei is also sung alternatim. In contrast to the Missa Misericordias Domini this mass includes passages in reduced scoring, one of the features of Franco-Flemish polyphony.

It is in most cases impossible to say how many singers were involved in performances of polyphonic music in the renaissance period. It is likely that in smaller chapels performances with one voice per part were common practice. However, in larger chapels - where the most famous composers worked - larger forces may have performed masses and motets like those recorded on these two discs. Cantica Symphonia comprises six singers but most pieces are performed with one voice per part. The Ensemble Gilles Binchois consists of nine singers; the tracklist doesn't indicate whether all of them are involved in the performance of the polyphony but that seems very likely. As the Missa Virgo prudentissima is for six voices, the difference with Cantica Symphonia is not substantial in this regard. The number of singers may be questionable from a historical point of view, it has the benefit of a large amount of transparency which allows for an optimal perception of all the voices. That is especially important in parody masses and in a mass where sometimes two texts are sung simultaneously, as in the Missa Virgo prudentissima.

Another issue is the use of instruments. The Ensemble Gilles Binchois omits any instruments, whereas Cantica Symphonia includes several strings and wind instruments as well as an organ in three items. Again, it is impossible to say when and in which pieces instruments might have been used. It was common practice at the time, but probably only at some special occasions. The instruments are prominently present in some of the pieces in Cantica Symphonia's programme, playing colla voce. In the second part of O decus Ecclesiae one passage is performed instrumentally; I wonder why that is the case.

The singing in both performances is excellent. The acoustic in the Cantica Symphonia recording is a little drier; these performances have also a little more intimacy whereas the Ensemble Gilles Binchois profits from a larger reverberation. Cantica Symphonia ends some phrases piano; I find that a little exaggerated, even a bit romantic. In the performance of the Ensemble Gilles Binchois the singing of plainchant by high and low voices in unison seems questionable; I wonder whether that was common practice at the time. It is interesting that at some moments the singers add a contratenor to the single written line, in the form of a falsobordone.

All in all, the release of these two discs deserves a wholehearted welcome. It is regrettable that Isaac's music is not more often performed and recorded. He fully deserves it as these two discs include wonderful music.